CWG3097 Lambda expression introduces a scope

Fixes NB AT 4-099 (C++26 CD).

Author: eisenwave

source/basic.tex

@@ -954,7 +954,8 @@
 declaration,
 \grammarterm{parameter-declaration-clause},
 \grammarterm{statement},
-\grammarterm{handler}, or
+\grammarterm{handler},
+\grammarterm{lambda-expression}, or
 contract assertion
 (as described in the following subclauses of \ref{basic.scope})
 appearing in another scope, which thereby contains $S$.